I wouldn't go as far to say the "evidence" is irrefutable, but when you compare it to other pairings, their dynamics and how Kishimoto built them up then NaruSaku's development has a much better chance of leading somewhere than something like NaruHina.
SasuSaku....idk what to say about it.
Kinda funny cause if you guys remember Escaflowne, the set up was similar but far less antagonism. The main heroine was in love with the second protagonist, but the main hero was in love with her, who also had a friend that was in love with him. What's funny about that set up was the girl (Hitomi) actually got to kiss her first love interest and their relationship had more romantic development. In the end, she comes to realise she loves the male protagonist in the last episode but they get separated in the end *shrugs*.
So it's not out there that Sakura might follow in the same direction. Will still be kitten but it's been done before. NaruSaku is in a better position because SasuSaku has kitten all romantic development from Sasuke's side. :)
I knew from the very beginning of "Escaflowne" that Hitomi was going to end up with the young king... obviously. Like most pairings in manga/anime/other series. Even when it's about harems, the hero/heroine usually chooses the first who he/she is attracted to (in broader sense). That can be considered a law of romance. There are exceptions, but those are exceptions that actually prove the rule. Shounen is not as predictable because the romance is blurred and deprived of clear signs. But it also conforms to the said law. NS is the most plausible option. More precisely put, it is the only option, threatened by the open ending.
Edited by Syn11, 15 October 2014 - 01:14 PM.